Stretch-cling films have wide application, including bundling packaged food and other goods. One application of particular interest is in the bundling of goods for shipping and storage, for example, the bundling of large rolls of carpet, fabric, or the like. A film having cling properties to prevent unraveling of the film from the pallet is therefore desirable. To impart cling properties or improve the cling properties of a particular film, a number of techniques have been employed, such as the addition of tackifying additives or use of polar ethylene copolymers such ethylene acrylates in the (co) polymer. Common tackifying additives include polybutenes, terpene resins, alkali metal and glycerol stearates, and oleates and hydrogenated rosins, and rosin esters.
Certain soft polyolefin polymers have been used to enhance cling properties of polyolefins. While at relatively low levels, the soft polymer tends to disperse in the polyolefin matrix, at higher levels the soft polymer tends to aggregate, forming domains within the polyolefin matrix, thereby placing an upper limit on the amount of soft polymer that can be incorporated for cling improvement. In other words, after a certain concentration, the addition of more of the soft polyolefin does not improve the cling performance and may contribute to other undesirable film properties such as blocking. In addition, cling performance can suffer in particular in dusty or low temperature environments. A composition suitable for cling films that can increase the cling performance of the film particularly in challenging environments would be useful. Methods of making and using such compositions and films would also be useful.
Background references include WO 00/69963.